Hydrocarbon substituted succinimides have long been used as lubricating oil dispersants. Such succinimides can be represented by U.S. Pat. Nos. 3,172,892, 3,202,678 and 3,219,666.
More recently, succinic groups have been grafted to high molecular weight olefin copolymers and then amidated to form dispersants having viscosity improving properties. Such products are represented by U.S. Pat. Nos. 3,235,503, 3,513,095, 4,089,794 and 4,219,432.